Semiconductor Processing System, and Control Assembly and Method Thereof

ABSTRACT

This disclosure relates to a semiconductor processing system, and control assembly and method thereof. The semiconductor processing system includes a mass flow controller (MFC), a control assembly and a process chamber. The MFC is coupled to a gas source to receive an input gas. The control assembly, which is coupled to the MFC, includes a charge chamber, an inlet valve and an outlet valve. The charge chamber is arranged to accommodate the input gas. The inlet valve is arranged to control a charge of the input gas for the charge chamber. The outlet valve is arranged to control a release of the input gas accommodated in the charge chamber. The process chamber is coupled to the outlet valve of the control assembly.

RELATED DISCLOSURE

This disclosure is a divisional of, and claims priority to, U.S. patentapplication Ser. No. 16/939,788 filed Jul. 27, 2020, which is herebyincorporated by reference herein in its entirety.

TECHNICAL FIELD

This disclosure relates to semiconductor processing systems and methods.

BACKGROUND

In semiconductor manufacturing field, atomic layer deposition (ALD) is apopular technique for forming a thin film. However, it has beendifficult to deliver precise and sufficient chemical dosage within avery short pulse time. The pulse time has routinely been relaxed toensure sufficient dosage and consistency, with negative impact onprocessing speed, precise dosage tuning and chemical consumption. It isdesirable to improve the processing method so that precise, repeatableand scalable chemical dosage can be controlled and delivered within avery short and fixed pulse time. Such improvement can lead to fasterprocessing speed, precise tuning of chemical dosage and more efficientuse of chemicals.

SUMMARY OF THE INVENTION

One of the objectives of the present disclosure is to provide asemiconductor processing system, a method of controlling thesemiconductor processing system, and a control assembly of thesemiconductor processing system to solve the problems mentioned above.Although some embodiments of the present disclosure are described withrespect to an ALD system or ALD operation, it is contemplated that thesolutions provided by the present disclosure can be applied to any othersuitable semiconductor processing system.

In some embodiments, a semiconductor processing system is disclosed. Thesemiconductor processing system includes a mass flow controller (MFC), acontrol assembly and a process chamber. The MFC is coupled to a gassource to receive an input gas. The control assembly, which is coupledto the MFC, includes a charge chamber, an inlet valve and an outletvalve. The charge chamber is arranged to accommodate the input gas. Theinlet valve is arranged to control a charge of the input gas for thecharge chamber. The outlet valve is arranged to control a release of theinput gas accommodated in the charge chamber. The process chamber iscoupled to the outlet valve of the control assembly.

In some embodiments, a method of controlling a semiconductor processingsystem is disclosed. The semiconductor processing system includes acontrol assembly coupled between a gas source and a process chamber. Themethod includes operating in a process stage, which includes: activatingan inlet valve of the control assembly coupled between the gas sourceand a charge chamber of the control assembly to charge the chargechamber with an input gas from the gas source; and activating a firstoutlet valve of the control assembly coupled between the charge chamberand the process chamber to release the input gas in the charge chamberinto the process chamber.

In some embodiments, a control assembly of a semiconductor processingsystem is disclosed. The control assembly includes an inlet valve, anoutlet valve and a charge chamber coupled between the inlet valve andthe outlet valve. The inlet valve, which is coupled between a gas sourceand the charge chamber, is arranged to control a charge of an input gasfrom a gas source for the charge chamber. The outlet valve, which iscoupled between the charge chamber and a process chamber, is arranged tocontrol a release of the input gas in the charge chamber to the processchamber.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 is a diagram illustrating a control assembly in accordance withan embodiment of the present disclosure.

FIG. 2 is a diagram illustrating operations of a control assembly inaccordance with an embodiment of the present disclosure.

FIG. 3 is a diagram illustrating a semiconductor processing system inaccordance with an embodiment of the present disclosure.

FIG. 4A is a diagram illustrating a semiconductor processing system inaccordance with another embodiment of the present disclosure.

FIG. 4B is a diagram illustrating the cooperation of a precursorsubsystem, a diluent gas subsystem and a purge gas subsystem in aprocess stage in accordance with an embodiment of the presentdisclosure.

FIG. 5A is a diagram illustrating a semiconductor processing system inaccordance with another embodiment of the present disclosure.

FIG. 5B is a diagram illustrating a semiconductor processing system inaccordance with another embodiment of the present disclosure.

FIG. 6 is a diagram illustrating a semiconductor processing system inaccordance with another embodiment of the present disclosure.

FIG. 7 is a diagram illustrating a semiconductor processing system inaccordance with another embodiment of the present disclosure.

FIG. 8 is a diagram illustrating the cooperation of a precursorsubsystem and a reactant subsystem in a process stage in accordance withan embodiment of the present disclosure.

FIG. 9 is a diagram illustrating a semiconductor processing system inaccordance with another embodiment of the present disclosure.

FIG. 10 is a diagram illustrating the cooperation of a diluent gassubsystem, a purge gas subsystem, a precursor subsystem and a reactantsubsystem in a process stage in accordance with an embodiment of thepresent disclosure.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the disclosure.Specific examples of components and arrangements are described below tosimplify the present disclosure. These are, of course, merely examplesand are not intended to be limiting. For example, the formation of afirst feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The device may be otherwise oriented (rotated 90 degrees orat other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the disclosure are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in therespective testing measurements. Also, as used herein, the term “about”generally means within 10%, 5%, 1%, or 0.5% of a given value or range.Alternatively, the term “about” means within an acceptable standarderror of the mean when considered by one of ordinary skill in the art.

Other than in the operating/working examples, or unless otherwiseexpressly specified, all of the numerical ranges, amounts, values andpercentages such as those for quantities of materials, durations oftimes, temperatures, operating conditions, ratios of amounts, and thelikes thereof disclosed herein should be understood as modified in allinstances by the term “about.” Accordingly, unless indicated to thecontrary, the numerical parameters set forth in the present disclosureand attached claims are approximations that can vary as desired.

At the very least, each numerical parameter should at least be construedin light of the number of reported significant digits and by applyingordinary rounding techniques. Ranges can be expressed herein as from oneendpoint to another endpoint or between two endpoints. All rangesdisclosed herein are inclusive of the endpoints, unless specifiedotherwise.

An atomic layer deposition (ALD) system relies on alternating dosage ofchemicals to achieve film deposition. A precursor chemical is firstdelivered to a work piece (e.g., a semiconductor wafer) in a reactor,resulting in chemisorption of the precursor molecule. If sufficientprecursor dosage is provided, the surface of the work piece becomesuniformly saturated with the precursor molecules. The reactor is thenevacuated with a purge gas and then supplied with a reactant chemicalthat can remove unwanted ligands from the precursor molecules on thesurface. This precursor/purge/reactant/purge sequence can be repeatedmultiple times and result in film deposition layer-by-layer until thedesired film thickness is achieved.

FIG. 1 is a diagram illustrating a control assembly 10 in accordancewith an embodiment of the present disclosure. In this presentdisclosure, the control assembly 10 is applied to a semiconductorprocessing system such as an ALD system. In some embodiments, thecontrol assembly 10 is coupled between a gas source and a processchamber of the semiconductor processing system. In some embodiments, thecontrol assembly 10 receives an input gas from the gas source, andreleases the input gas into the process chamber for executingsemiconductor processing (e.g., an ALD operation) upon the work piece(e.g., a semiconductor wafer) in the process chamber.

The control assembly 10 includes a charge chamber 11, an inlet valve 12,and outlet valves 13 and 14. The charge chamber 11, coupled between theinlet valve 12 and the outlet valves 13 and 14, is arranged toaccommodate the input gas. The inlet valve 12, which is coupled to thegas source via a gas line 110, is arranged to control charge of theinput gas from the gas source for the charge chamber 11. The outletvalves 13 and 14 are arranged to control release of the input gas in thecharge chamber 11. The outlet valve 13 is coupled to the processchamber, and the outlet valve 14 is coupled to a dump line. Therefore,the outlet valve 13 controls the release of the input gas in the chargechamber 11 to the process chamber, and the outlet valve 14 controls therelease of the input gas in the charge chamber 11 to the dump line.

In some embodiments, the control assembly 10 may further include otherelements to achieve the function. For example, the control assembly 10may further include a pressure transducer 15 coupled to the chargechamber 11. The pressure in the charge chamber 11 is monitored by thepressure transducer when the inlet valve 12 is open.

In some embodiments of the present disclosure, the input gas may be acarrier gas. In other embodiments of the present disclosure, the inputgas may be a reactant gas. The chemical dosage in the input gas isgathered and held in the charge chamber 11. The volume of the chargechamber 11 is designed to be sufficiently large to hold chemical dosagerequired for one pulse. When the input gas flow is injected continuouslyinto the charge chamber 11, the line pressure of the gas line 110increases with time. For a reactant gas, the chemical dosage held by thecharge chamber 11, in moles, equals to P_(Line) V/RT, where P_(Line) isthe line pressure, V is the volume of the charge chamber 11, R is theideal gas constant and T is the absolute temperature of the chargechamber 11. Increasing the input gas flow and/or charge time results inincreasing dosage held by the charge chamber 11. For a carrier gas, thechemical dosage of the carried precursor, held by the charge volume 11,increases with the carrier gas flow and the charge time until thepartial pressure of the carried vapor reaches the vapor pressure in theprecursor tank. The maximum accumulation for a carried vapor in thecharge chamber 11 is P₀ V/RT, where P₀ is the vapor pressure of theprecursor in the precursor tank, V is the volume of the charge chamber11, R is the ideal gas constant and T is the absolute temperature of thecharge chamber 11.

When the control assembly 10 operates, the inlet valve 12 and the outletvalve 13 (or the outlet valve 14) are sequentially activated. That is,when the inlet valve 12 is activated, the outlet valves 13 and 14 aredeactivated. When one of the outlet valves 13 and 14 is activated, theinlet valve 12 and the other outlet valve are deactivated.

Specifically, when the inlet valve 12 is activated, the input gas ischarged into the charge chamber 11. In the meantime, the outlet valves13 and 14 are deactivated. When the outlet valve 13 is activated, theinput gas in the charge chamber 11 is released into the process chamber.In the meantime, the inlet valve 12 and the outlet valve 14 aredeactivated. When the outlet valve 14 is activated, the input gas in thecharge chamber 11 is released into the dump line. In the meantime, theinlet valve 12 and the outlet valve 13 are deactivated.

Regardless of which outlet valve is activated, the downstream pressureshould be much lower than the pressure in the charge chamber 11 at theonset of the release step. Hence, the release step can be completedwithin a fraction of a second. In addition, the line pressure of the gasline 110 is expected to drop momentarily when the inlet valve 12 isactivated, and the line pressure will rise when the inlet valve 12 isdeactivated during the release step.

In some embodiments of the present disclosure, standard pneumatic on/offvalves can be used to implement the inlet valve 12 and the outlet valves13 and 14. However, the type of valve used to implement the inlet valve12 and the outlet valves 13 and 14 is not a limitation of the presentdisclosure.

FIG. 2 is a diagram illustrating operations of the control assembly inaccordance with an embodiment of the present disclosure. When thesemiconductor processing system (e.g., an ALD system) applying thecontrol assembly 10 starts to operates, the pressure in the chargechamber 11 and the chemical dosage of the input gas will take multiplecharge and release cycles before reaching a stable and repeatable state.During the initial and transition stage, the pressure in the chargechamber 11 and the chemical dosage vary from cycle to cycle, which isnot suitable for executing an ALD operation. Therefore, the input gas inthe charge chamber 11 is not used for the ALD operation and releasedinto the dump line.

Specifically, in the transition stage, activating durations of the inletvalve 12 and the outlet valve 14 are staggered. An activating durationof a valve refers to a period of time in which the valve is open oractivated. Moreover, the inlet valve 12 and the outlet valve 14 aresequentially and repeatedly activated. When the inlet valve 12 isactivated, the input gas is charged into the charge chamber 11, and thepressure in the charge chamber 11 gradually increases. When the outletvalve 14 is activated, the input gas in the charge chamber 11 isreleased into the dump line, and the pressure in the charge chamber 11gradually decreases. By this, a cycle of charge/release in thetransition stage is completed.

The transition stage lasts for several cycles of charge/release, whereinthe pressure in the charge chamber 11 and the chemical dosage in theinput gas gradually stabilize with each cycle of charge/release. Afterthe transition stage, the pressure in the charge chamber 11 and thechemical dosage of the input gas become stable and repeatable forexecuting the ALD operation, and then a process stage can start.Therefore, in the process stage, the input gas in the charge chamber 11is used for the ALD operation and released into the process chamber. Theline pressure is constantly monitored by the pressure transducer 15,installed upstream from the inlet valve 12, to determine if and when thetransition stage has ended and the process stage can start.

Specifically, in the process stage, activating durations of the inletvalve 12 and the outlet valve 13 are staggered. Moreover, the inletvalve 12 and the outlet valve 13 are sequentially and repeatedlyactivated. When the inlet valve 12 is activated, the input gas ischarged into the charge chamber 11, and the pressure in the chargechamber 11 gradually increases. When the outlet valve 13 is activated,the input gas in the charge chamber 11 is released into the processchamber to process the work piece (e.g., a semiconductor wafer), and thepressure in the charge chamber 11 gradually decreases. By this, a cycleof charge/release in the process stage is completed.

FIG. 3 is a diagram illustrating a semiconductor processing system 30applying the control assembly 10 in accordance with an embodiment of thepresent disclosure. In addition to the control assembly 10, thesemiconductor processing system 30 further includes a precursorsubsystem. The precursor subsystem includes a carrier gas source 31, amass flow controller (MFC) 32, a precursor tank 33, a dump line 34, anda plurality of valves 361 to 367. The semiconductor processing system 30further includes a process chamber 35.

The carrier gas source 31 provides a carrier gas, as the input gasmentioned above, to the precursor tank 33 via the MFC 32 when the valve361 is activated. The precursor tank 33 is coupled between the MFC 32and the control assembly 10 via the valves 362 to 367. The precursortank 33 receives the carrier gas and provides precursor vapor in thecarrier gas. The dump line 34 and the process chamber 35 arerespectively coupled to the outlet valves 14 and 13 of the controlassembly 10. The functions of the dump line 34 and the process chamber35 are described in the embodiment of FIG. 2 . The detailed descriptionis omitted here for brevity.

When the semiconductor processing system 30 starts to operate, thecarrier gas source 31 is turned on to provide the carrier gas, and theflow rate of the carrier gas is set for the MFC 32. The carrier gasflows into the precursor tank 33 and carries precursor vapor out intothe gas line 110. After a predetermined time period of initialcharge/release cycles (i.e., the transition stage), the continuousoperation of the sequential charge and release process (i.e., theprocess stage) described in the embodiment of FIG. 2 will be executed.

If the precursor tank 33 is properly designed and operated, the carriergas provided by the carrier gas source 31 should enter the chargechamber 11 with saturated precursor. The molar flow rate of thesaturated precursor equals to the carrier molar flow rate divided by(P_(Line)/(P₀−P_(V))−1), where P_(Line) and P_(V) are the total pressureand the precursor partial pressure of the gas line 110, respectively,and P₀ is the vapor pressure in the precursor tank 33. As P_(Line) andP_(V) increase gradually during charging, the molar flow rate of thecarried precursor will decrease with time. The rate of precursoraccumulation will diminish when P_(V) approaches P₀ after a prolongedcharge. Therefore, the maximum precursor dosage that can be accumulatedin the charge chamber 11 equals to P₀ V/RT. The volume of the chargechamber should be as large as possible to allow high maximum dosagewhile the carrier gas flow rate should be as high as possible to allowfast dosage accumulation. The optimal choice for the volume of thecharge chamber and the carrier gas flow rate shall result in precise andconsistent accumulation during each charge step and discharge duringeach release step.

In some embodiments, the semiconductor processing system 30 can furtheroperates in an offline purge stage, in which the carrier gas is used asthe purge gas to remove any remaining precursor molecules in the gasline 110. This type of purge is critical in maintaining cleanliness andsafety for precursors with strong reactivity with oxygen/moisture and toprevent unavoidable condensation/accumulation of low vapor pressureprecursors on the cold spots in the gas line 110.

Specifically, in the offline purge stage, the valves 365 and 367 aredeactivated while the valves 362, 363, 364, and 366, the inlet valve 12and the outlet valve 14 are activated, which provides a pathway foroffline purging of the gas line 110 and the charge chamber 11.Alternatively, the valves 365 and 367 can be manual valves and remainopen during the offline purge stage when the valves 364, 363 and 366 aredeactivated while the valve 362, the inlet valve 12 and the outlet valve14 are activated to facilitate offline purging of the gas line 110 andthe charge chamber 11.

FIG. 4A is a diagram illustrating a semiconductor processing system 40applying the control assembly 10 in accordance with an embodiment of thepresent disclosure. The semiconductor processing system 40 is similar tothe semiconductor processing system 30 described and illustrated in theembodiment of FIG. 3 except that the semiconductor processing system 40further includes a diluent gas subsystem and a purge gas subsystem. Thediluent gas subsystem includes a diluent gas source 41, a MFC 42, adiluent inlet valve 43 and a diluent outlet valve 44. The diluent gassubsystem provides a continuous stream of inert gas to the processchamber 35 when the diluent inlet valve 43 and the diluent outlet valve44 are activated. The purge gas subsystem includes a purge gas source51, a MFC 52, a purge inlet valve 53 and two purge outlet valves 54 and55. The purge gas source 51 provides a purge gas to the process chamber35, when the purge inlet valve 53 and the purge outlet valve 54 areactivated and the purge outlet valve 55 is deactivated. Alternatively,the purge gas flow is diverted to the dump line 56 when the purge inletvalve 53 and the purge outlet valve 55 are activated and the purgeoutlet valve 54 is deactivated. The diluent gas subsystem and the purgegas subsystem are used for processing as well as for cleaning. Thesimilarities between the semiconductor processing system 40 and thesemiconductor processing system are omitted here for brevity.

FIG. 4B is a diagram illustrating the cooperation of the precursorsubsystem, the diluent gas subsystem and the purge gas subsystem in theprocess stage in accordance with an embodiment of the presentdisclosure. The operations of the precursor subsystem and the controlassembly are similar to those described and illustrated in FIGS. 2 and 3.

Referring to FIG. 4B in conjunction with FIG. 4A, in the process stage,when the inlet valve 12 and the purge outlet valve 54 are activated atthe same time, the purge gas source 51 provides a high flow rate ofpurge gas to the charge chamber 11. On the other hand, when the outletvalve 13 and the purge outlet valve 55 are activated at the same time,the purge gas is diverted to the dump line while the dosage is releasedfrom the charge chamber 11 to the process chamber 35. During the chargerelease step, the diluent gas source 41 provides a low flow rate ofdiluent gas to the released charge before entering the process chamber35.

The mass flow rate of the diluent gas is selected to achieve the bestpossible chemical distribution and film uniformity on the working pieceunder processing. The mass flow rate of the purge gas is selected sothat the remaining precursor vapor in the gas line and in the processchamber 35 can be quickly swept away. Both the diluent and the purge gascan be the same inert gas, such as N2, Ar or He, and introduceddownstream from the outlet valve 13 but before the process chamber 35.

FIG. 5A is a diagram illustrating a semiconductor processing system 401applying the control assembly 10 in accordance with an embodiment of thepresent disclosure. The semiconductor processing system 401 is similarto the semiconductor processing system 40 described and illustrated inthe embodiment of FIG. 4A except that the semiconductor processingsystem 401 includes a plurality of control assemblies 10 connected tothe process chamber 35.

When a control assembly 10 operates in the release step, i.e., theoutlet valve 13 is activated to release the carrier gas in the chargechamber 11 to the process chamber 35, the other control assemblies 10operate in the charge step, i.e., the inlet valve 12 is activated tocharge the carrier gas into the charge chamber 11. In this embodiment,the plurality of control assemblies 10 sequentially operate in therelease step. Those skilled in the art should understand that theplurality of control assemblies 10 ensure dosage scalability, whichallows convenient and expedient process optimization during processdevelopment and quick adjustment during manufacturing when changes, suchas surface area and/or film performance requirements, occur, requiringfine tuning for chemical dosage.

It should be noted that, in other embodiments, the operator candetermine how many control assemblies will be used together at the sametime for one process chamber 35. For example, two control assemblies 10in the semiconductor processing system 401 operate in the release stepat the same time, and other control assemblies 10 in the semiconductorprocessing system 401 operate in the charge step.

FIG. 5B is a diagram illustrating a semiconductor processing system 402applying the control assembly 10 in accordance with an embodiment of thepresent disclosure. The semiconductor processing system 402 is similarto the semiconductor processing system 40 described and illustrated inthe embodiment of FIG. 4A except that the semiconductor processingsystem 402 includes a plurality of control assemblies 10, a plurality ofdiluent gas subsystems, a plurality of purge gas subsystems, and aplurality of process chambers 35. Each process chamber 35 corresponds toa control assembly 10, a diluent gas subsystem and a purge gassubsystem.

The semiconductor processing system 402 can selectively operates in aparallel mode or a sequential mode. When the semiconductor processingsystem 402 operates in the parallel mode, each control assembly 10 isassigned to the corresponding process chamber 35. The control assemblies10 can perform charge/release step in parallel, therefore, semiconductorprocessing procedures in all process chambers 35 can be performedsimultaneously.

When the semiconductor processing system 402 operates in the sequentialmode, each control assembly is programmed to serve the process chambers35 sequentially. For example, assuming the semiconductor processingsystem 402 includes two control assemblies 10 and two process chambers35, one control assembly 10 is used for the first process chamber 35first, followed by the other control assembly 10 used for the secondprocess chamber 35 in alternating release cycles. The sequential modeallows more charge time and higher release dosage while each processchamber 35 take turns in receiving the dosage.

Based on the dosage requirement and the number of process chambers inthe system, the operator can determine how many control assemblies 10will be used together at the same time and the sequence of operation foreach control assembly.

The concepts illustrated for FIGS. 5A and 5B can be further combinedtogether to achieve unlimited flexibility and precision in dosagedelivery to one or many process chambers—all with a single set ofcarrier gas source, MFC and precursor tank, allowing the maximum dosagecontrol capability at the lowest cost.

FIG. 6 is a diagram illustrating a semiconductor processing system 60applying the control assembly 10 in accordance with an embodiment of thepresent disclosure. In addition to the control assembly 10, thesemiconductor processing system 60 further includes a reactantsubsystem. The reactant subsystem includes a reactant gas source 61, aMFC 62, a dump line 63, and a valve 65. The reactant gas source 61provides a reactant gas, as the input gas mentioned above, to thecontrol assembly 10 via the MFC 62 when the valve 65 is activated. Thesemiconductor processing system 60 further includes a process chamber64. The functions of the dump line 63 and the process chamber 64 aredescribed in the embodiment of FIG. 2 .

When the semiconductor processing system 60 starts to operate, thereactant gas source 61 is turned on to provide the reactant gas, and theflow rate of the reactant gas is set for the MFC 62. The reactant gasflows into the gas line 110 of the control assembly 10. After apredetermined time period of initial charging (i.e., the transitionstage), the continuous operation of the sequential charge and releaseprocess (i.e., the process stage) described in the embodiment of FIG. 2will be executed.

For gaseous reactants, the volume of the charge chamber 11 should besufficiently large to prevent sharp pressure rise approaching 1 atm.Since the pressure rise is determined by mass flow rate times cycle timedivided by the charge volume. The volume of the charge chamber 11 can beeasily determined by setting an upper pressure rise limit such as around100-500 torr.

Those skilled in the art should readily understand that, after readingthe embodiments of FIGS. 4A, 5A and 5B, the semiconductor processingsystem 60 can be expanded as the semiconductor processing system 40, 401or 402. The detailed description is omitted here for brevity.

FIG. 7 is a diagram illustrating a semiconductor processing system 70applying the control assembly 10 in accordance with an embodiment of thepresent disclosure. The semiconductor processing system 70 includes aprecursor subsystem which includes a carrier gas source 31′, a MFC 32′,a precursor tank 33′, a dump line 34′, and a plurality of valves 361′ to367′. The precursor subsystem of the semiconductor processing system 70is similar to that described and illustrated in the embodiment of FIG. 3. Therefore, the detailed description of each element is omitted here.

The semiconductor processing system 70 further includes a reactantsubsystem which includes a reactant gas source 61′, a MFC 62′, a dumpline 63′, and a valve 65′. The reactant subsystem of the semiconductorprocessing system 70 is similar to that described and illustrated in theembodiment of FIG. 6 . Therefore, the detailed description of eachelement is omitted here.

The precursor subsystem and the reactant subsystem are connected, viarespective control assemblies 10, to a process chamber 71 for executingsemiconductor processing such as an ALD operation. Specifically, theoutlet valves 13 of the precursor subsystem and the reactant subsystemare connected to a process chamber 71.

When the semiconductor processing system 70 operates in the transitionstage, the inlet valve 12 and the outlet valve 14 of the precursorsubsystem are sequentially and repeatedly activated to release thecarrier gas in the charge chamber 11 of the precursor subsystem untilthe pressure and the chemical dosage are stable. Likewise, when thesemiconductor processing system 70 operates in the transition stage, theinlet valve 12 and the outlet valve 14 of the reactant subsystem aresequentially and repeatedly activated to release the reactant gas in thecharge chamber 11 of the reactant subsystem until the pressure and thechemical dosage are stable. The operations of the precursor subsystemand the reactant subsystem in the transition stage are described in theembodiment of FIG. 2 . The detailed description is omitted here forbrevity.

FIG. 8 is a diagram illustrating the cooperation of the precursorsubsystem and the reactant subsystem in the process stage in accordancewith an embodiment of the present disclosure. Referring to FIG. 8 inconjunction with FIG. 7 , for the precursor subsystem, in the processstage, the activating durations of the inlet valve 12 and the outletvalve 13 are staggered. Specifically, the inlet valve 12 and the outletvalve 13 are sequentially and repeatedly activated. Moreover, theprecursor pulse is generated for executing the ALD operation when theoutlet valve 13 is activated.

Likewise, for the reactant subsystem, in the process stage, theactivating durations of the inlet valve 12 and the outlet valve 13 arestaggered. Specifically, the inlet valve 12 and the outlet valve 13 aresequentially and repeatedly activated. Moreover, the reactant pulse isgenerated for executing the ALD operation when the outlet valve 13 isactivated. Furthermore, the activating durations of the outlet valves 13of the precursor subsystem and the reactant subsystem are staggered.Specifically, the outlet valves 13 of the precursor subsystem and thereactant subsystem are sequentially and repeatedly activated.

FIG. 9 is a diagram illustrating a semiconductor processing system 90applying the control assembly 10 in accordance with an embodiment of thepresent disclosure. The semiconductor processing system 90 is similar tothe semiconductor processing system 70 described and illustrated in theembodiment of FIG. 7 except that the semiconductor processing system 90further includes a diluent gas subsystem and a purge gas subsystem. Thediluent gas subsystem includes a diluent gas source 41′, a MFC 42′, adiluent inlet valve 43′ and a diluent outlet valve 44′. The purge gassubsystem includes a purge gas source 51′, a MFC 52′, a purge inletvalve 53′ and two purge outlet valves 54′ and 55′. The diluent gas andthe purge gas subsystems of the semiconductor processing system 90 aresimilar to the diluent gas and the purge gas subsystems described andillustrated in the embodiment of FIG. 4A.

FIG. 10 is a diagram illustrating the cooperation of the diluent gas andthe purge gas subsystems, the precursor subsystem and the reactantsubsystem in the process stage in accordance with an embodiment of thepresent disclosure. The operations of the precursor subsystem and thereactant subsystem are similar to that described and illustrated in FIG.8 . The operations of the precursor subsystem and the reactant subsystemare omitted here for brevity.

Referring to FIG. 10 in conjunction with FIG. 9 , in the process stage,the purge gas source 51′ provides the purge gas with a high flow ratewhen the inlet valve 12 of the precursor subsystem, the inlet valve 12of the reactant subsystem and the purge outlet valve 54′ are activated.On the other hand, in the process stage, the diluent gas source 41′provides the diluent gas with a low flow rate when the diluent outletvalve 44′ of the diluent gas subsystem is activated.

While this disclosure has been described with specific embodimentsthereof, it is evident that many alternatives, modifications, andvariations may be apparent to those skilled in the art. For example,various components of the embodiments may be interchanged, added, orsubstituted in the other embodiments. Also, all of the elements of eachfigure are not necessary for operation of the disclosed embodiments. Forexample, those having ordinary skills in the art would be enabled tomake and use the teachings of the disclosure by simply employing theelements of the independent claims. Accordingly, embodiments of thedisclosure as set forth herein are intended to be illustrative, notlimiting. Various changes may be made without departing from the spiritand scope of the disclosure.

What is claimed is:
 1. A method of controlling a semiconductorprocessing system including a control assembly coupled between a massflow controller (MFC) and a process chamber, the method comprising:operating in a process stage, comprising: providing an input gas from agas source to a precursor tank via the MFC, the precursor tank coupledbetween the MFC and the control assembly and providing a precursor vaporin the inlet gas to allow the input gas carrying the precursor vapor;activating an inlet valve of the control assembly coupled between thegas source and a charge chamber of the control assembly to charge thecharge chamber with the input gas carrying the precursor vapor; andactivating a first outlet valve of the control assembly coupled betweenthe charge chamber and the process chamber to release the input gas inthe charge chamber into the process chamber.
 2. The method of claim 1,wherein activating durations of the inlet valve and the first outletvalve are staggered in the process stage.
 3. The method of claim 2,wherein the inlet valve and the first outlet valve are activatedsequentially and repeatedly in the process stage.
 4. The method of claim1, further comprising: operating in a transition stage, comprising:activating the inlet valve to charge the charge chamber with the inputgas carrying the precursor vapor; and activating a second outlet valveof the control assembly coupled between the charge chamber and a dumpline.
 5. The method of claim 4, wherein activating durations of theinlet valve and the second outlet valve are staggered in the transitionstage.
 6. The method of claim 5, wherein the inlet valve and the secondoutlet valve are activated sequentially and repeatedly in the transitionstage.
 7. The method of claim 3, further comprising: operating in anoffline purging stage, comprising: activating the inlet valve and thesecond outlet valve simultaneously to clean a gas line coupled betweenthe gas source and the charge chamber.
 8. The method of claim 1, whereinthe gas source is a carrier gas source, the input gas is a carrier gas,the control assembly is a first control assembly, the semiconductorprocessing system further includes a second control assembly coupledbetween a reactant gas source and the process chamber, and operating inthe process stage further comprises: activating an inlet valve of thesecond control assembly coupled between the reactant gas source and acharge chamber of the second control assembly to charge the chargechamber of the second control assembly with a reactant gas from thereactant gas source; and activating an outlet valve of the secondcontrol assembly coupled between the charge chamber of the secondcontrol assembly and the process chamber to release the reactant gasinto the process chamber.
 9. The method of claim 8, wherein activatingdurations of the inlet valve of the second control assembly and theoutlet valve of the second control assembly are staggered in the processstage.
 10. The method of claim 9, wherein the inlet valve of the secondcontrol assembly and the outlet valve of the second control assembly areactivated sequentially and repeatedly in the process stage.
 11. Themethod of claim 10, wherein activating durations of the first outletvalve of the first control assembly and the outlet valve of the secondcontrol assembly are staggered.
 12. The method of claim 11, whereinoperating in the process stage further comprises: providing a purge gasinto the process chamber with a first flow rate when the inlet valve ofthe first control assembly and the inlet valve of the second controlassembly are both activated and the first outlet valve of the firstcontrol assembly and the outlet valve of the second control assembly areboth deactivated; and providing the purge gas into a dump line when theoutlet valve of the first control assembly or the outlet valve of thesecond control assembly is activated.
 13. The method of claim 12,wherein operating in the process stage further comprises: continuouslyproviding a diluent gas into the process chamber with a second flowrate, wherein the first flow rate is higher than the second flow rate.